Camera

ABSTRACT

A camera comprising a mode setting portion in which either mode is set out of a first focusing mode and a second focusing mode. The camera includes: a mode switch, detecting means, focusing means, and focusing mode controlling means for performing such a control. After completion of focusing when the period detected by the detecting means is longer than a predetermined period and the second focusing mode is set or when the first focusing mode is set the mode is switched to the first focusing mode. The present invention provides a camera which permits the user to select either the operation in which the mode change is performed every shot or the operation in which a same mode is continuously maintained, by the period in which the mode switch is kept on.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a camera, and more particularly to acamera provided with an autofocus mechanism (automatic focusingmechanism), which permits a user to designate whether the autofocusmechanism is to be on or off, and a camera having a motorized manualfocus mechanism for achieving focus at a distance designated by theuser.

2. Related Background Art

Many recent cameras have the autofocus mechanism for automaticallyadjusting focus. The autofocus methods are roughly classified into thepassive method and the active method.

The passive method is one for measuring a distance, using the sameprinciple as the triangulation and utilizing contrast of an object.Namely, because the contrast becomes highest when twin images come intocoincidence with each other as in a rangefinder, the lens is moved so asto achieve the highest contrast, thereby achieving focus.

The active method is one for determining a position of the lens byemitting light or sound of a certain wavelength from the camera to theobject and obtaining a distance from an angle or a time of the light orsound reflected by the object back to the camera.

As described, the cameras provided with the autofocus mechanism(so-called autofocus cameras) permit a photographer to take photographswithout manually attaining focus, thus being very convenient. However,because focusing by the autofocus mechanism is carried out based onmeasurement of the distance between the camera and the object, it had aproblem that distance measurement took a considerable time for taking aphotograph of a very far object such as a distant view. Then, solvingthis problem, there are conventionally developed autofocus camerasprovided with an infinity mode (far-field mode) for taking a photographwhile fixing focus at infinity, in addition to the autofocus mode. Whenthis type of camera is used to take a photograph in the infinity mode,focus is fixed at infinity without driving the autofocus mechanism,whereby a distant view can be quickly photographed.

The conventional autofocus cameras provided with the infinity mode,however, are normally constructed in such an arrangement that theyoperate in the autofocus mode unless the infinity mode is designated andthat even if they are turned once into the infinity mode, they alwaysreturn to the original autofocus mode as soon as a shutter releasebutton is depressed. Thus, they had a problem that for continuouslytaking a plurality of photographs in the infinity mode, mode settingmust be repeated every after shooting.

Meanwhile, focusing by the autofocus mechanism requires that the objectis always located at the center of screen. It was thus difficult toachieve correct focus by the autofocus mechanism in cases of takingphotographs of an object moving at high speed and in cases of takingphotographs of an object located near an edge of screen. Then, there arecommercially available cameras having a manual focus mechanism forpermitting the photographer to manually attain focus in cases of takingphotographs of such special objects. In focusing by such a manual focusmechanism, the user manipulates a focus dial (focal length setting dial)provided in the upper part or the like of camera. Numerals indicatingdistances are written on the surface of the focus dial, and the userdesignates a focal length by rotating the focus dial while referring tothe numerals. When the shutter release button is depressed, themotorized focus mechanism is driven to achieve focus on an objectlocated apart at the distance.

It was, however, difficult for the user to designate a focal length aslooking at the numerals on the focus dial while holding the camera inposition. Thus, the user needed to change the holding state of cameraonce for manipulating the focus dial.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a camera having aninterface excellent in operability of changeover between the autofocusmode and another focusing mode, for example such as the infinity mode.

Another object of the present invention is to provide a camera having aninterface excellent in operability, particularly upon shooting withmanual setting of a focal length.

The present invention provides a camera comprising:

(a) a mode setting portion in which either mode is set out of a firstfocusing mode and a second focusing mode;

(b) a mode switch (for example, a switch having a push button) capableof being switched between an off state and an on state, the mode switchalternately switching a mode set in the mode setting portion between thefirst focusing mode and the second focusing mode every activation of theon state;

(c) detecting means for detecting a period in which the mode switch iskept in the on state;

(d) focusing means for performing focusing according to the mode set inthe mode setting portion in synchronization with a shutter releasebutton; and

(e) focusing mode controlling means for performing such a control, aftercompletion of the focusing by the focusing means,

that when the period detected by the detecting means is longer than apredetermined period and when the mode set in the mode setting portionis the second focusing mode, the mode set in the mode setting portion isheld in the second focusing mode,

that when the period detected by the detecting means is shorter than thepredetermined period and when the mode set in the mode setting portionis the second focusing mode, the mode set in the mode setting portion isswitched from the second focusing mode to the first focusing mode, and

that when the mode set in the mode setting portion is the first focusingmode, the mode set in the mode setting portion is held in the firstfocusing mode.

The first focusing mode is preferably an autofocus mode in which thefocusing means performs focusing to achieve focus according to adistance between the camera and an object. Further, the second focusingmode is preferably either a fixed focus mode in which the focusing meansachieves focus at a specific focal length or a manual focus mode inwhich the focusing means achieves focus at a focal length manuallydesignated.

In the above camera of the present invention, when the user turns themode switch into the on state while the mode set in the mode settingpotion is kept in the first focusing mode (for example, in the autofocusmode), the mode set in the mode setting portion is switched from thefirst focusing mode to the second focusing mode (for example, to thefixed focus mode or the manual focus mode). The detecting means detectsthe period in which the mode switch is kept in the on state.

If the period detected by the detecting means is shorter than thepredetermined period, the focusing mode controlling means again sets thefirst focusing mode in the mode setting portion after completion of thefocusing by the focusing means. On the other hand, if the perioddetected by the detecting means is longer than the predetermined period,the mode set in the mode setting portion is held in the second focusingmode even after completion of the focusing by the focusing means.Further, if the mode is switched from the second focusing mode to thefirst focusing mode, the mode set in the mode setting portion is alsoheld in the first focusing mode after completion of the focusing by thefocusing means, regardless of the period detected by the detectingmeans.

Thus, if the mode is switched from the first focusing mode to the secondfocusing mode by turning on the mode switch for a period shorter thanthe predetermined period, the mode returns to the original firstfocusing mode after the shutter button is pressed once.

In contrast with it, if the mode is switched from the first focusingmode to the second focusing mode by keeping the mode switch in the onstate for a period not less than the predetermined period, the mode isalways held in the second focusing mode, irrespective of how many timesthe shutter release button is pressed, before the mode switch is nextturned into the on state.

Further, the present invention provides a camera comprising:

(a) a mode setting portion in which either mode is set out of a firstfocusing mode, a second focusing mode, and a third focusing mode;

(b) a mode switch (for example, a switch having a push button) capableof being switched between an off state and an on state, the mode switchsuccessively switching a mode set in the mode setting portion among thefirst focusing mode, the second focusing mode, and the third focusingmode every activation of the on state;

(c) detecting means for detecting a period in which the mode switch iskept in the on state;

(d) focusing means for performing focusing according to the mode set inthe mode setting portion in synchronization with a shutter releasebutton; and

(e) focusing mode controlling means for performing such a control, aftercompletion of the focusing by the focusing means,

that when the period detected by the detecting means is longer than apredetermined period and when the mode set in the mode setting portionis either the second focusing mode or the third focusing mode, the modeset in the mode setting portion is held as it is,

that when the period detected by the detecting means is shorter than thepredetermined period and when the mode set in the mode setting portionis either the second focusing mode or the third focusing mode, the modeset in the mode setting portion is switched to the first focusing mode,and

that when the mode set in the mode setting portion is the first focusingmode, the mode set in the mode setting portion is held in the firstfocusing mode.

The first focusing mode is preferably the autofocus mode in which thefocusing means achieves focus according to the distance between thecamera and the object. Also, the second focusing mode is preferably thefixed focus mode in which the focusing means achieves focus at aspecific focal length. Further, the third focusing mode is preferablythe manual focus mode in which the focusing means achieves focus at afocal length manually designated.

In the above camera of the present invention, when the user turns themode switch into the on state once or twice while the mode set in themode setting portion is kept in the first focusing mode (for example,the autofocus mode), the mode set in the mode setting portion isswitched from the first focusing mode into the second focusing mode (forexample, the fixed focus mode) or the third focusing mode (for example,the manual focus mode). The detecting means detects the period in whichthe mode switch is kept in the on state.

If the period detected by the detecting means is shorter than thepredetermined period, the focusing mode controlling means again sets thefirst focusing mode in the mode setting portion after completion of thefocusing by the focusing means. On the other hand, if the perioddetected by the detecting means is longer than the predetermined period,the mode set in the mode setting portion is maintained as it is evenafter completion of the focusing by the focusing means. Further, if themode is switched from either the second or third focusing mode to thefirst focusing mode, the mode set in the mode setting portion is alsoheld in the first focusing mode, regardless of the period detected bythe detecting means, after completion of the focusing by the focusingmeans.

Thus, if the mode is switched from the first focusing mode to the secondfocusing mode or the third focusing mode by keeping the mode switch inthe on state for the period shorter than the predetermined period, themode is returned to the original first focusing mode after the shutterrelease button is pressed once.

In contrast with it, if the mode is switched from the first focusingmode to the second focusing mode or the third focusing mode by keepingthe mode switch in the on state for the period not less than thepredetermined period, the focusing mode set is always held as it is,independently of how many times the shutter release button is pressed,before the mode switch is next turned into the on state.

Further, the present invention provides a camera comprising:

focal length designating means capable of being switched between an offstate and an on state, the focal length designating means acceptingdesignation of a focal length in the on state and outputting dataconcerning the focal length;

a clock circuit for outputting data concerning a time;

a display for displaying either data out of the data concerning thefocal length and the data concerning the time;

focusing means for performing focusing to achieve focus at a focallength designated through the focal length designating means insynchronization with a shutter release button; and

display controlling means for displaying the data concerning the focallength on the display when the focal length designating means is kept inthe on state and displaying the data concerning the time on the displaywhen the focal length designating means is kept in the off state.

In a preferred embodiment, the focal length designating means comprises

a storing portion for storing a plurality of focal length data, and

focal length data controlling means for successively outputting dataconcerning the focal length by successively reading the focal lengthdata at predetermined time intervals out of the plurality of focallength data stored in the storing portion while the focal lengthdesignating means is kept in the on state, the focal length datacontrolling means accepting, as a focal length designated, focal lengthdata read out when the focal length designating means is switched fromthe on state to the off state. In this case, if the focal lengthdesignating means is kept in the on state, the display controlling meanssuccessively displays the data concerning the focal length output fromthe focal length designating means, on the display.

In an embodiment of the above camera of the present invention, thedisplay comprises

first and second segments for displaying respective numerals, and

a third segment disposed between the first segment and the secondsegment, the third segment being provided for displaying either one of acolon and a period;

wherein when the focal length designating means is kept in the on state,the display controlling means displays the data concerning the focallength in the first, second, and third segments and wherein when thefocal length designating means is kept in the off state, the displaycontrolling means displays the data concerning the time in at least thefirst and second segments.

Another embodiment of the above camera of the present invention furthercomprises a switch for alternately switching the data concerning thetime between data of a date and data of a real time;

wherein the display controlling means controls the display in such amanner

that for displaying the data concerning the focal length, the first,second, and third segments display the data and the third segmentdisplays a period,

that for displaying the data of the real time, the first, second, andthird segments display the data and the third segment displays a colon,and

that for displaying the data of the date, at least the first and secondsegments display the data.

According to the above camera of the present invention, when the userdesignates a focal length, the focal length designating means receivesthe focal length designated. The data concerning the focal length thusreceived is displayed on the display by the display controlling meanswhile the focal length designating means is kept in the on state,whereby the user can visually recognize that the focal length iscorrectly accepted. When the user depresses the shutter release buttonafter confirming that the focal length accepted is correct, the focusingmeans automatically achieves focus at the focal length.

Here, if the focal length designating means comprises the above storingportion and the focal length data controlling means and when the userturns the focal length designating means into the on state, the distancedata is successively read at predetermined time intervals out of aplurality of focal length data stored in the storing portion. Thedistance data thus read out is successively displayed on the display bythe display controlling means. When the user observing the displayswitches the focal length designating means into the off state afterdesired focal length data is displayed on the display, reading-out ofthe focal length data is suspended, and focal length data read out atthat time is accepted as a focal length designated. The finally read-outfocal length data is continuously displayed on the display. After that,when the user depresses the shutter release button, the focusing meansachieves focus at the focal length designated (which is a distanceindicated by the focal length data finally read out).

Further, the above camera of the present invention is arranged todisplay the data concerning the focal length on the display which isarranged normally to display the data concerning the time, therebyenabling to display the data concerning the focal length without using aseparate display (segments).

The present invention will be more fully understood from the detaileddescription given hereinbelow and the accompanying drawings, which aregiven by way of illustration only and are not to be considered aslimiting the present invention.

Further scope of applicability of the present invention will becomeapparent from the detailed description given hereinafter. However, itshould be understood that the detailed description and specificexamples, while indicating preferred embodiments of the invention, aregiven by way of illustration only, since various changes andmodifications within the spirit and scope of the invention will beapparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view to show the appearance of an example of anautofocus camera according to the present invention;

FIG. 2 is a block diagram to show the structure of an example of acontrol unit according to the present invention;

FIG. 3 is a flowchart to show the details of an example of processing bythe control unit according to the present invention;

FIG. 4 is a flowchart to show the details of the example of processingby the control unit according to the present invention;

FIG. 5 is a flowchart to show the details of the example of processingby the control unit according to the present invention;

FIG. 6 is a flowchart to show the details of the example of processingby the control unit according to the present invention;

FIG. 7 is a flowchart to show the details of the example of processingby the control unit according to the present invention;

FIG. 8A to FIG. 8E are each drawings to show examples of screen displayon a liquid crystal display according to the present invention;

FIG. 9A to FIG. 9E are each drawings to show examples of screen displayon the liquid crystal display according to the present invention; and

FIG. 10 is a drawing to show another example of screen display on theliquid crystal display according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

An embodiment of the present invention will be explained by reference tothe accompanying drawings. FIG. 1 is a perspective view to show theappearance of an autofocus camera according to the present embodiment.Referring to FIG. 1, the autofocus camera of the present embodiment hasa shutter release button 11 disposed on the top surface of a rectangularparallelepiped body 10, and a distance-measuring device 12 for measuringa distance between the camera and an object is incorporated in the toppart of the front surface of body 10. This distance-measuring device 12employs the passive method for obtaining the distance to the object byemitting light to the object and measuring a contrast of reflected lightfrom the object. A lens barrel 13 in which lenses are incorporated ismounted in the central portion of the front surface of body 10. The lensbarrel 13 has a double-barrel structure, which is arranged to expand orcontract an inner barrel by driving a built-in motor 14. This expansionor contraction changes the distance between the film and the lens set inthe inner barrel, thereby achieving focus at a desired distance.

Further, there are a power-supply switch 15 disposed in the center ofthe upper part of the back face of body 10 and a liquid crystal display17 disposed on a back lid 16 in the back face of body 10. This liquidcrystal display 17 indicates by the segment type display method dataconcerning the time (for example, data of a date such as"year-month-day", "month-day-year", or "day-month-year", or data of areal time such as "month-day-hour", "day-hour-minute", or"hour-minute-second") or data concerning the focal length. A mode switch18 and a focal length switch (focal length designating means) 19 arehorizontally arranged below the liquid crystal display 17, and switches20-22 are horizontally arranged in the upper part of the back face ofbody 10. The mode switch 18 is a push button switch for selecting eithermode out of an autofocus mode, a fixed focus mode, and a manual focusmode, and is arranged to successively change the selected mode everytime the push button is forced down (into an on state). Also, the focallength switch 19 is a push button switch for the user to manuallydesignate a desired focal length in the manual focus mode, and isarranged to successively change focal length data designated every timethe push button is forced down (into an on state), to be displayed onthe liquid crystal display 17.

Here, the autofocus mode is a mode in which the distance-measuringdevice 12 measures the distance from the camera to the object and focusis achieved at this distance. The fixed focus mode is a mode in whichfocus is fixed at infinity. Further, the manual focus mode is a mode inwhich focus is achieved at a focal length designated by the user.

The present embodiment is arranged to detect the period during which thepush button of the mode switch 18 is forced down when the selected modeis changed from the autofocus mode to the fixed focus mode or from theautofocus mode to the manual focus mode, using the mode switch 18. Ifthis period is shorter than a predetermined period (for example, threeseconds), single-shot shooting is allowed in the changed mode (eitherthe fixed focus mode or the manual focus mode) and thereafter the modeis returned to the autofocus mode. If the period detected is not lessthan the predetermined period (for example, three seconds), the changedmode (either the fixed focus mode or the manual focus mode) is heldbefore the mode switch 18 is next forced down.

For performing such processing, the autofocus camera of the presentembodiment includes a control unit 30 shown in the block diagram of FIG.2.

In FIG. 2, the control unit 30 is provided with a control portion (focusmode controlling means) 31, which is a detecting means for detecting theperiod during which the push button of the mode switch 18 is forced downand which changes the mode set in the mode setting portion into theautofocus mode if the period detected is shorter than the predeterminedperiod (for example, three seconds) and if the mode set is either thefixed focus mode or the manual focus mode. The control portion 31 has amode setting portion 31a and a latch setting portion 31b, and either onemode is set in the mode setting portion 31a out of the "autofocus mode",the "fixed focus mode", and the "manual focus mode". Either "latch on"or "latch off" is set in the latch setting portion 31b.

"Latch on" is set if the period during which the push button of the modeswitch 18 is forced down is not less than the predetermined period (forexample, three seconds), whereas "latch off" is set if the period duringwhich the push button of the mode switch 18 is forced down is less thanthe predetermined period (for example, three seconds). If "latch on" isset in the latch setting portion 31b, the same mode is maintained afterthe shutter release button 11 is depressed in either the fixed focusmode or the manual focus mode. In contrast with it, if "latch off" isset in the latch setting portion 31b, the mode is changed over into theautofocus mode after the shutter release button 11 is depressed ineither the fixed focus mode or the manual focus mode.

The control unit 30 has a focal length storing portion 32 for storingdata of a plurality of different focal lengths, such as 0.3 m, 0.4 m,0.5 m, 0.6 m, 0.7 m, 0.8 m, 0.9 m, 1.0 m, 1.2 m, 1.5 m, 2.0 m, 2.5 m,3.0 m, 5.0 m, 10.0 m, 30.0 m, and ∞, and a timer 33 for measuring aperiod during which the push button of the mode switch is or the focallength switch 19 is forced down. The focal length data stored in thefocal length storing portion 32 have respective reading ranks differentfrom each other, and are read out in order according to the readingranks by the control portion (focal length data controlling means) 31while the push button of the focal length switch 19 is forced down.

Further, the control unit 30 has a clock circuit 34 and a quartzoscillator 35. Pulse signals output from the quartz oscillator 35 areinput into the clock circuit 34, and the clock circuit 34 counts anaccurate time, based on the pulse signals, and outputs data concerningthe time.

Furthermore, the control unit 30 has a display control portion 36, andthe display control portion 36 receives the data concerning the timecounted by the clock circuit 34 and the data concerning the focal lengthread out from the focal length storing portion 32. The display controlportion 36 causes the liquid crystal display 17 to indicate the dataconcerning the time or the focus, based on these data.

The control unit 30 receives a signal from the shutter release button11, the focal length data from the distance-measuring device 12, and amaking signal from the power-supply switch 15. Receiving the signal fromthe shutter release button 11, the control unit 30 supplies a controlsignal to the motor 14 in accordance with the mode set in the modesetting portion 31a.

The details of the processing by the control unit 30 are next explainedusing the flowcharts in FIG. 3 to FIG. 7 and the drawings of examples ofscreen indications in FIG. 8A-FIG. 8E and FIG. 9A-FIG. 9E.

This processing is started when the user turns on the power-supplyswitch 15. As shown in FIG. 3, receiving a making signal of thepower-supply switch 15, the control portion 31 sets the "autofocus mode"in the mode setting portion 31a and "latch off" in the latch settingportion 31b (step 100). Next, the display control portion 36 sends acontrol signal to the liquid crystal display 17 so that the liquidcrystal display 17 is turned on to display a numeral sequence indicatingthe data concerning the time counted by the clock circuit 34 (step 101).Based on this control signal, the liquid crystal display 17 displays theimage as shown in FIG. 8A. Then it is checked whether either one ispressed out of the mode switch 18, the focal length switch 19, and theswitches 20-22 (step 102), and in case of neither switch being pressed,whether the shutter release button 11 is depressed is checked (step103).

When the shutter release button 11 is depressed, the control unit 30sends a control signal to the motor 14, based on the data set in themode setting portion 31a (step 104). Specifically, if the "autofocusmode" is set in the mode setting portion 31a, the control unit 30 sendsto the motor 14 a control signal for expanding or contracting the lensbarrel 13 so that focus is attained at the distance indicated by thefocal length data input from the distance-measuring device 12. If the"fixed focus mode" is set in the mode setting portion 31a, the controlunit 30 sends to the motor 14 a control signal for expanding orcontracting the lens barrel 13 so as to achieve focus at infinity.Further, if the "manual focus mode" is set in the mode setting portion31a, the control unit 30 sends to the motor 14 a control signal forexpanding or contracting the lens barrel 13 so as to achieve focus at afocal length selected by the user using the focal length switch 19.

It is next checked whether the "autofocus mode" is set in the modesetting portion 31a (step 105), and unless the "autofocus mode" is set,what is set in the latch setting portion 31b is then checked (step 106).If "latch off" is set in the latch setting portion 31b, the "autofocusmode" is set in the mode setting portion 31a (step 107) to return theprocessing to step 102. The processing is also returned to step 102 ifthe shutter release button 11 is not depressed at step 103, if the"autofocus mode" is set in the mode setting portion 31a at step 105, andif "latch on" is set in the latch setting portion 31b at step 106.

If either switch is depressed at step 102, the control unit 30 checkswhich switch is depressed (step 108). If either the mode switch 18 orthe focal length switch 19 is pressed, associated processing as detailedlater will be performed. If either switch 20-22 is depressed, it ischecked whether the switch is now on (step 109), and if it is onprocessing associated with the switch is executed (step 110). Theprocessing is returned to step 102 if the switch is already turned offat step 109 or if the processing of step 110 is finished.

Next explained referring to FIG. 4 is the processing executed when themode switch 18 is pressed at step 108.

In FIG. 4, it is first checked whether the mode switch 18 is on (step120). If the mode switch 18 is on, "latch off" is set in the latchsetting portion 31b (step 121). Then, what is set in the mode settingportion 31a is checked (step 122), and if the "autofocus mode" is set,the timer 33 is started (step 123). Further, the "fixed focus mode" isset in the mode setting portion 31a (step 124) and the display controlportion 36 sends a control signal to the liquid crystal display 17 so asto flash an "INF" mark on the upper left part of the liquid crystaldisplay 17 (step 125). Based on this control signal, the image as shownin FIG. 8B is displayed on the liquid crystal display 17.

While indicating such a display, it is checked with the timer 33 whetherthe predetermined time (for example, three seconds) has elapsed afterthe mode switch 18 was pressed (steps 126, 127). If the mode switch 18is still on at a lapse of the predetermined time, "latch on" is set inthe latch setting portion 31b (step 128). Then the display controlportion 36 sends a control signal to the liquid crystal display 17 so asto light to display a "LATCH" mark on the upper right part of the liquidcrystal display 17 (step 129). Based on this control signal, the imageas shown in FIG. 8C is displayed on the liquid crystal display 17.

If the mode switch 18 is turned off after completion of the processingof step 129 (step 130), the timer 33 is stopped (step 131). Then thedisplay control portion 36 sends a control signal to the liquid crystaldisplay 17 so as to light to display the "INF" mark on the upper leftpart of the liquid crystal display 17 (step 132). Based on this controlsignal, the image as shown in FIG. 8D is displayed on the liquid crystaldisplay 17.

If the mode switch 18 is turned off before the predetermined time (forexample, three seconds) has elapsed after the mode switch 18 was pressed(step 127), the timer 33 is also stopped (step 131). Then the displaycontrol portion 36 sends a control signal to the liquid crystal display17 so as to light to display the "INF" mark on the left upper part ofthe liquid crystal display 17 (step 132). Based on this control signal,the image as shown in FIG. 8E is displayed on the liquid crystal display17.

Next explained with FIG. 5 is the processing executed when the "fixedfocus mode" is set in the mode setting portion 31a at step 122.

In FIG. 5, first, the display control portion 36 sends a control signalto the liquid crystal display 17 so as to switch off the numeralsequence indicating the data concerning the time, displayed on theliquid crystal display 17 (step 140). Further, the display controlportion 36 sends a control signal to the liquid crystal display 17 so asto switch off the "INF" mark and the "LATCH" mark displayed on theliquid crystal display 17 (step 141). Then the timer 33 is started (step142), and the "manual focus mode" is set in the mode setting portion 31a(step 143).

Next, the display control portion 36 sends a control signal to theliquid crystal display 17 so as to flash an "m" mark on the lower rightpart of the liquid crystal display 17 (step 144). Further, the focallength data with the smallest reading rank is read out of the pluralityof focal length data stored in the portion 32, and the display controlportion 36 sends a control signal to the liquid crystal display 17 so asto display it on the central portion of the liquid crystal display 17(step 145). Based on these control signals, the image as shown in FIG.9A is displayed on the liquid crystal display 17.

While indicating such a display, it is checked with the timer 33 if thepredetermined time (for example, three seconds) has elapsed after themode switch 18 was pressed (steps 146, 147). If the mode switch 18 isstill on at a lapse of the predetermined time, "latch on" is set in thelatch setting portion 31b (step 148). Then the display control portion36 sends a control signal to the liquid crystal display 17 so as tolight to display the "LATCH" mark on the upper right portion of theliquid crystal display 17 (step 149). Based on this control signal, theimage as shown in FIG. 9B is displayed on the liquid crystal display 17.

If the mode switch 18 is turned off after completion of the processingof step 149 (step 150), the timer 33 is stopped (step 151). Then thedisplay control portion 36 sends a control signal to the liquid crystaldisplay 17 so as to light to display the "m" mark on the lower rightpart of the liquid crystal display 17 (step 152). Further, the displaycontrol portion 36 sends a control signal to the liquid crystal display17 so as to light to display the focal length data read out of the focallength storing portion 32, in the central portion of the liquid crystaldisplay 17 (step 153). Based on these control signals, the image asshown in FIG. 9C is displayed on the liquid crystal display 17.

If the mode switch 18 is turned off before the predetermined time (forexample, three seconds) has elapsed after the mode switch 18 was pressed(step 147), the timer 33 is also stopped (step 151). Then the displaycontrol potion 36 sends a control signal to the liquid crystal display17 so as to light to display the "m" mark on the lower right part of theliquid crystal display 17 (step 152). Further, the display controlportion 36 sends a control signal to the liquid crystal display 17 so asto light to display the focal length data read out of the focal lengthstoring portion 32, in the central portion of the liquid crystal display17 (step 153). Based on these control signals, the image as shown inFIG. 9D is displayed on the liquid crystal display 17.

Next explained with FIG. 6 is the processing executed when the "manualfocus mode" is set in the mode setting portion 31a at step 122.

In FIG. 6, first, the display control portion 36 sends a control signalto the liquid crystal display 17 so as to switch off the data concerningthe focal length, displayed on the liquid crystal display 17 (step 160).Next, the display control portion 36 sends a control signal to theliquid crystal display 17 so as to switch off the "LATCH" mark and the"m" mark displayed on the liquid crystal display 17 (step 161). Further,the "autofocus mode" is set in the mode setting portion 31a (step 162),and the display control portion 36 sends a control signal to the liquidcrystal display 17 so as to light to display a numeral sequenceindicating the data concerning the time counted by the clock circuit 34,on the liquid crystal display 17 (step 163). Based on these controlsignals, the image as shown in FIG. 9E is displayed on the liquidcrystal display 17. Then the control unit waits until the mode switch 18is turned off, and then returns the processing to step 102 when the modeswitch 18 is turned off.

Next explained with FIG. 7 is the processing executed when the focallength switch 19 is pressed at step 108.

In FIG. 7, first, whether the focal length switch 19 is on is checked(step 170). If the focal length switch 19 is on, it is checked whetherthe "manual focus mode" is set in the mode setting portion 31a (step171). If the "manual focus mode" is set in the mode setting portion 31a,the next focal length data is read out of the focal length storingportion 32 (step 172). Further, the display control portion 36 sends acontrol signal to the liquid crystal display 17 so as to light todisplay the focal length data thus read out, in the central portion ofthe liquid crystal display 17 (step 173), and the timer 33 is started(step 174).

While the focal length data is indicated on the liquid crystal display17, it is checked with the timer 33 whether the predetermined time (forexample, a half second) has elapsed after the focal length switch 19 waspressed (steps 175, 176). If the focal length switch 19 is still on at alapse of the predetermined time, the timer 33 is restarted (step 177).Subsequently, the further next focal length data is read out of thefocal length storing portion 32 (step 178), and the display controlportion 36 sends a control signal to the liquid crystal display 17 so asto light to display the focal length data in the central portion of theliquid crystal display 17, and then the processing is returned to step175.

If the focal length switch 19 is turned off before the predeterminedtime (for example, a half second) has elapsed after the focal lengthswitch 19 was pressed (step 176), the timer 33 is stopped (step 180).The processing is also returned to step 102 if the focal length switch19 is off at step 170, if the "manual focus mode" is not set in the modesetting portion 31a at step 171, and if the processing of step 180 isfinished.

While the user continues pressing the focal length switch 19, the loopprocessing of steps 175 to 180 reads the focal length data atpredetermined time intervals (for example, of a half second) from thesmallest reading rank out of the plurality of focal length data (0.3 m,0.4 m, 0.5 m, 0.6 m, . . . ) stored in the focal length storing portion32. After the focal length data with the largest reading rank is readout, reading returns to the focal length data with the smallest readingrank, and is repeated up to the highest therefrom. Since the focallength data thus read out is displayed in order on the liquid crystaldisplay 17, the user can readily select desired focal length data.

Further, as shown in FIG. 9C and FIG. 9E, indications of the focallength data on the liquid crystal display 17 are given using a segment40 for indications of numerals indicating "month", a segment 41 forindications of numerals indicating "day", and a part (lower part) of asegment 42 for an indication of a colon disposed between the segments 40and 41 in the display of the data concerning the time ("year-month-day"in the present embodiment). Since the liquid crystal display 17 employsthe segment type display method as discussed above, it is preferred inrespect of durability and cost reduction to decrease the number ofsegment electrodes by common use of the segments as much as possible fordisplaying two types of screens, for example the display of the dataconcerning the time and the display of the data concerning the focallength.

Thus, the present embodiment is arranged to have the segment 40 fordisplay of numerals indicating "month" in the data concerning the timefor common use to the segment 50 for display of numerals indicatingintegral parts in the focal length data. The embodiment also has thesegment 41 for display of numerals indicating "day" in the dataconcerning the time for common use to the segment 51 for display ofnumerals indicating decimal parts in the focal length data. Further, theembodiment also has a part (lower segment) of the segment 42 for displayof a colon (for example, in case of "day-hour-minute" being displayed asthe data concerning the time as shown in FIG. 10, a colon is displayedbetween "hour" and "minute") disposed between the segments 40 and 41 forcommon use to the segment 52 for display of a decimal point in the focallength data.

The common use of the various segments enabled the at least two types ofscreens to be efficiently displayed on the liquid crystal display 17without increasing the number of segments.

The present invention can be changed or modified in various formswithout having to be limited to the above embodiment. For example, thepresent embodiment used the passive distance-measuring device 12, butthe present invention does not have to be limited to thisdistance-measuring method, and can employ an active distance-measuringdevice. Further, the present embodiment used the liquid crystal display17 as a display means, but another display device may be employed, forexample ELD (electroluminescent display) or PD (plasma display).

In a preferred example, the apparatus is provided with a switch foralternately changing the data concerning the time displayed on theliquid crystal display 17 between the data of a date as shown in FIG.8A-FIG. 8E and FIG. 9E (for example, "year-month-day") and the data of areal time as shown in FIG. 10 (for example, "day-hour-minute").

Further, the present embodiment used the focal length switch 19 of thepush button type to read out the focal length data, but the switch maybe of a dial type.

As detailed above, the present invention can provide a camera with aninterface excellent in operability for user, which permits the user toselect either the operation in which the mode change is performed everyshot (one-shot return) or the operation in which a same mode iscontinuously maintained, by the period in which the mode switch is kepton (for example, by forcing it down).

Further, the present invention can provide a camera excellent in visualoperability, which permits the user to visually check whether the focallength designated by the user is correctly accepted, because the focallength designated by the user is displayed on the display screen by thedisplaying means. Further, the camera of the present invention isarranged to display the data concerning the focal length in the displaynormally displaying the data concerning the time, thereby enabling todisplay the data concerning the focal length without using a separatedisplay (segments).

From the invention thus described, it will be obvious that the inventionmay be varied in many ways. Such variations are not to be regarded as adeparture from the spirit and scope of the invention, and all suchmodifications as would be obvious to one skilled in the art are intendedfor inclusion within the scope of the following claims.

The basic Japanese Application Nos. 247866/1994 (6-247866) filed on Oct.13, 1994, and 247877/1994 (6-247877) filed on Oct. 13, 1994, are herebyincorporated by reference.

What is claimed is:
 1. A camera comprising:(a) a mode setting portion inwhich either mode is set out of a first focusing mode and a secondfocusing mode; (b) a mode switch capable of being switched between anoff state and an on state, said mode switch alternately switching a modeset in said mode setting portion between said first focusing mode andsaid second focusing mode every activation of the on state; (c)detecting means for detecting a period in which said mode switch is keptin the on state; (d) focusing means for performing focusing according tothe mode set in said mode setting portion in synchronization with ashutter release button; and (e) focusing mode controlling means forperforming such a control, after completion of the focusing by saidfocusing means, that when the period detected by said detecting means islonger than a predetermined period and when the mode set in said modesetting portion is said second focusing mode, the mode set in said modesetting portion is held in said second focusing mode, that when theperiod detected by said detecting means is shorter than thepredetermined period and when the mode set in said mode setting portionis said second focusing mode, the mode set in said mode setting portionis switched from said second focusing mode to said first focusing mode,and that when the mode set in said mode setting portion is said firstfocusing mode, the mode set in said mode setting portion is held in saidfirst focusing mode.
 2. A camera according to claim 1, wherein saidfirst focusing mode is an autofocus mode and said focusing meansperforms focusing according to a distance between the camera and anobject in said autofocus mode and wherein said second focusing mode is afixed focus mode and said focusing means performs focusing to achievefocus at a specific focal length in said fixed focus mode.
 3. A cameraaccording to claim 1, wherein said first focusing mode is an autofocusmode and said focusing means performs focusing according to a distancebetween the camera and an object in said autofocus mode and wherein saidsecond focusing mode is a manual focus mode and said focusing meansperforms focusing to achieve focus at a focal length manually designatedin said manual focus mode.
 4. A camera according to claim 1, whereinsaid mode switch is a switch having a push button and said detectingmeans detects a period between after the push button is pressed andbefore said push button is released, as the period in which said modeswitch is kept in the on state.
 5. A camera according to claim 1,further comprising focal length designating means capable of beingswitched between an off state and an on state, said focal lengthdesignating means accepting designation of a focal length in the onstate and outputting data concerning the focal length when the mode setin said mode setting portion is said second focusing mode;a clockcircuit for outputting data concerning a time; a display for displayingeither data out of said data concerning the focal length and said dataconcerning the time; and display controlling means for displaying saiddata concerning the focal length on said display when said focal lengthdesignating means is kept in the on state and displaying said dataconcerning the time on said display when said focal length designatingmeans is kept in the off state; wherein when the mode set in said modesetting portion is said second focusing mode, said focusing meansperforms focusing to achieve focus at the focal length designatedthrough said focal length designating means.
 6. A camera according toclaim 5, wherein said focal length designating means comprisesa storingportion for storing a plurality of focal length data, and focal lengthdata controlling means for successively outputting data concerning thefocal length by successively reading the focal length data atpredetermined time intervals out of the plurality of focal length datastored in said storing portion while said focal length designating meansis kept in the on state, said focal length data controlling meansaccepting, as a focal length designated, focal length data read out whensaid focal length designating means is switched from the on state to theoff state; wherein when said focal length designating means is kept inthe on state, said display controlling means successively displays thedata concerning the focal length output from said focal lengthdesignating means, on said display.
 7. A camera according to claim 5,wherein said display comprisesfirst and second segments for displayingrespective numerals, and a third segment disposed between said firstsegment and said second segment, said third segment being provided fordisplaying either one of a colon and a period; wherein when said focallength designating means is kept in the on state, said displaycontrolling means displays said data concerning the focal length in saidfirst, second, and third segments and wherein when said focal lengthdesignating means is kept in the off state, said display controllingmeans displays said data concerning the time in at least said first andsecond segments.
 8. A camera according to claim 5, further comprising aswitch for alternately switching said data concerning the time betweendata of a date and data of a real time;wherein said display controllingmeans controls the display in such a manner that for displaying saiddata concerning the focal length, said first, second, and third segmentsdisplay said data and said third segment displays a period, that fordisplaying said data of the real time, said first, second, and thirdsegments display said data and said third segment displays a colon, andthat for displaying said data of the date, at least said first andsecond segments display said data.
 9. A camera comprising:(a) a modesetting portion in which either mode is set out of a first focusingmode, a second focusing mode, and a third focusing mode; (b) a modeswitch capable of being switched between an off state and an on state,said mode switch successively switching a mode set in said mode settingportion among said first focusing mode, said second focusing mode, andsaid third focusing mode every activation of the on state; (c) detectingmeans for detecting a period in which said mode switch is kept in the onstate; (d) focusing means for performing focusing according to the modeset in said mode setting portion in synchronization with a shutterrelease button; and (e) focusing mode controlling means for performingsuch a control, after completion of the focusing by said focusing means,that when the period detected by said detecting means is longer than apredetermined period and when the mode set in said mode setting portionis either said second focusing mode or said third focusing mode, themode set in said mode setting portion is held as it is, that when theperiod detected by said detecting means is shorter than thepredetermined period and when the mode set in said mode setting portionis either said second focusing mode or said third focusing mode, themode set in said mode setting portion is switched to said first focusingmode, and that when the mode set in said mode setting portion is saidfirst focusing mode, the mode set in said mode setting portion is heldin said first focusing mode.
 10. A camera according to claim 9, whereinsaid first focusing mode is an autofocus mode and said focusing meansperforms focusing according to a distance between the camera and anobject in said autofocus mode, wherein said second focusing mode is afixed focus mode and said focusing means performs focusing to achievefocus at a specific focal length in said fixed focus mode, and whereinsaid third focusing mode is a manual focus mode and said focusing meansperforms focusing to achieve focus at a focal length manually designatedin said manual focus mode.
 11. A camera according to claim 9, whereinsaid mode switch is a switch having a push button and said detectingmeans detects a period between after the push button is pressed andbefore said push button is released, as the period in which said modeswitch is kept in the on state.
 12. A camera according to claim 9,further comprising focal length designating means capable of beingswitched between an off state and an on state, said focal lengthdesignating means accepting designation of a focal length in the onstate and outputting data concerning the focal length when the mode setin said mode setting portion is said third focusing mode;a clock circuitfor outputting data concerning a time; a display for displaying eitherdata out of said data concerning the focal length and said dataconcerning the time; and display controlling means for displaying saiddata concerning the focal length on said display when said focal lengthdesignating means is kept in the on state and displaying said dataconcerning the time on said display when said focal length designatingmeans is kept in the off state; wherein when the mode set in said modesetting portion is said third focusing mode, said focusing meansperforms focusing to achieve focus at the focal length designatedthrough said focal length designating means.
 13. A camera according toclaim 12, wherein said focal length designating means comprisesa storingportion for storing a plurality of focal length data, and focal lengthdata controlling means for successively outputting data concerning thefocal length by successively reading the focal length data atpredetermined time intervals out of the plurality of focal length datastored in said storing portion while said focal length designating meansis kept in the on state, said focal length data controlling meansaccepting, as a focal length designated, focal length data read out whensaid focal length designating means is switched from the on state to theoff state; wherein when said focal length designating means is kept inthe on state, said display controlling means successively displays thedata concerning the focal length output from said focal lengthdesignating means, on said display.
 14. A camera according to claim 12,wherein said display comprisesfirst and second segments for displayingrespective numerals, and a third segment disposed between said firstsegment and said second segment, said third segment being provided fordisplaying either one of a colon and a period; wherein when said focallength designating means is kept in the on state, said displaycontrolling means displays said data concerning the focal length in saidfirst, second, and third segments and wherein when said focal lengthdesignating means is kept in the off state, said display controllingmeans displays said data concerning the time in at least said first andsecond segments.
 15. A camera according to claim 12, further comprisinga switch for alternately switching said data concerning the time betweendata of a date and data of a real time;wherein said display controllingmeans controls the display in such a manner that for displaying saiddata concerning the focal length, said first, second, and third segmentsdisplay said data and said third segment displays a period, that fordisplaying said data of the real time, said first, second, and thirdsegments display said data and said third segment displays a colon, andthat for displaying said data of the date, at least said first andsecond segments display said data.